Experimental Validation of an Elastic-Plastic Contact Model

Abstract

In many engineered structures and components, impact events frequently occur between sub-components. Numerical models are able to adequately capture the salient features of these events; however, with high fidelity finite element models, an unreasonably large number of elements are needed to accurately model just the elastic regime when arbitrary contact is considered. In order to solve real engineering problems with elastic-plastic impacts in complex or built up systems, an analytical expression is needed to make solutions practical. To this end, a series of experiments are designed to test a new elastic plastic model for impact dynamics. A hard metal ball is attached as the end of a pendulum, and is struck against a relatively compliant metal puck. Digital image analysis is used to measure the displacement and velocity of the metal ball across the impact events. Frictional losses in the system are minimized, and the coefficient of restitution is calculated as a function of velocity. These measurements are used to validate an elastic-plastic impact model, which is further compared to and other models from the literature. Good agreement is found between the new analytical model and the experiments.